Need to measure HERTZ

[Deaf Bob]

My wife's Buick Century with a 3.1 V-6 seems to have a bad MAF sensor... I need to check the hertz signal.. My meter reads ohms and voltage..
I'm pretty sure..been 25 years since school in electronics..that ohms measures resistance, which is what hertz is...
Or so I need a different muiti-meter?

http://easyautodiagnostics.com/gm_maf_diagnostic/maf_gm_tests_2.php

This is what I'm trying to do...

Got stranded 30 miles from home.. Ran poor then would not go.. Idles better with new fuel filter.. But will not accelerate.. Feels/acts like a bad accelerator pump..
With the MAF at $200, I'd like to be 100% sure that's the problem..
My son can hear the fuel pump working
No CEL shows ...

[Barry Donovan]

should be able to do resistance.
I wonder why hertz.
dieselgeek must know this.

maybe they are testing the clock.. which is silly. that would be ecu.

[SuperBuickGuy]

Ohms, voltage and Hertz measure 3 different things (resistance, potential, and speed).... I don't think any volt meter measures frequency - ones that do are the spendy machines you need an oscilloscope

[Deaf Bob]

Ohms, voltage and Hertz measure 3 different things.... I don't think any volt meter measures frequency - ones that do are the spendy machines you need an oscilloscope

That is what I'm afraid I remember....
I am pretty sure ohms will not work!
My multimeter will do ac/dc/ohms..

[squirrel]

Hertz is a unit of frequency. Some fancy digital voltmeters have a frequency counter in them, or you can use a standalone frequency counter, or an oscilloscope. My guess is you probably don't really want to get that far into it.

being deaf, it's not surprising you don't know as much about Hertz as us who can hear frequency.

[Deaf Bob]

So... How else do you tell if the MAF is any good?

What gets me is no CEL lights are on..

Idles rough and has no throttle response.. Took 4-6 restarts and feathering the throttle to get it on the trailer..

What else will it be? Fuel pump? Will an electric in tank pump not pump enough pressure if it's bad?

[DanStokes]

Assuming you have a Big Box auto parts store nearby (AutoZone, etc.) they'll check it for you thru the OBD port. That should be an OBD I (I think), depending on the year. Anyhow - I'd trailer it over and have them bring out their meter. Cost = $0.00. And they'll have the part right there whatever the meter shows. Worth a try. If you have a friend with a 'scope - or a Fluke multimeter (big bux) - they could check it, too.

Dan

[Beagle]

http://easyautodiagnostics.com/multimeter_recommendation/digital_multimeter_hertz_1.php

http://www.amazon.com/gp/product/B000JQ4O2U?ie=UTF8&tag=easyautodiagn-20&linkCode=as2&camp=1789&creative=9325&creativeASIN=B000JQ4O2U

35.00

I didn't know that they had meters which would measure cycles per second (hertz). Cool deal. I thought it took a scope. Live and learn!

It'd be cheaper than the fuel pump that I think you are right in suspecting to find out. I'd consider putting a gauge on the fuel rail first.

[squirrel]

I'd consider putting a gauge on the fuel rail first.

me too especially if the pump is old or if it's been a while since you've changed the filter.

There are lots of parts that can go bad and cause similar symptoms....

[SuperBuickGuy]

http://easyautodiagnostics.com/multi...er_hertz_1.php

http://www.amazon.com/gp/product/B000JQ4O2U?ie=UTF8&tag=easyautodiagn-20&linkCode=as2&camp=1789&creative=9325&creativeASIN=B000JQ4O2U

35.00

I didn't know that they had meters which would measure cycles per second (hertz). Cool deal. I thought it took a scope. Live and learn!

It'd be cheaper than the fuel pump that I think you are right in suspecting to find out. I'd consider putting a gauge on the fuel rail first.

I'd be careful of anything that is 1/4 the price of something else and has bonus features. Fluke is actually right down the street from me, and they are a high-automated, highly-regarded company who are very cost-conscious (the parking lot is full of econoboxes, as opposed to Microsoft). That said, all the kids in the family are getting free HF digital multimeters as stocking stuffers for Christmas

[Deaf Bob]

This is the only fuel injected car I have.
What kind of pressure am I supposed to be looking for?
All I know is fuel injected motors run more pressure.. Not how much more..

[Beagle]

GM with throttle body is something like 15psi I think. Port injection should be 43.

[JOES66FURY]

Fluke is the only way to go when buying a quality meter.

We use Fluke exclusively at work, nothing else will do.

[dieselgeek]

Fluke is overpriced and unnecessary outside of a professional environment. A cheap Actron will measure frequency, I've been using one to do this for 4-5 years now, I think it cost $40?

Anyhow, Bob - the quick way to diagnose a bad MAF sensor is to disconnect it. The engine computer will have a backup mode called "Speed Density" that should get you home. From the description of the problem I doubt it's the MAF sensor though.

There will be a schrader valve (same as used to fill your tires with air) on the fuel rial, the very first thing I'd check is fuel pressure. Usually the pump will "prime" for a couple seconds when the key is turned to the On position. if not, crank it a bit and try to get it running and see if you have pressure. The fuel pressure will fluctuate a bit and that's OK because the regulator is connected to vacuum in the intake manifold. Look for around 30psi when idling, and around 43-45psi running. It might be as simple as a clogged fuel filter.

If you have fuel pressure then look at the ignition system. Other things to look at are a leaking intake manifold, vacuum lines, etc.

[Huskinhano]

I use to work at their world headquarters for 18 years. You can get a digital V.O.M. from HF cheap that will read hertz and temp. On alternating current you do need to know hertz as well as Henries to calculate impedance which is the AC version of DC resistance.